Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various control surfaces or components. One type of actuator that has been designed and implemented is a linear actuator. The actuator is driven by a rotary motor, such as certain types of electromechanical or rotary hydraulic actuators.
In many instances an electromechanical actuator (EMA) is mounted between two self aligning bearings, also known as spherical, monoball or rod end bearings. Many EMA configurations have the motor aligned with the linear line of action, which is parallel to a line between two self aligning bearings. As the actuator motor changes direction, an inertial torque is transferred to the actuator housing. When this occurs, the actuator housing may rotate within the self aligning bearings. This rotational movement can result in high impact loads should the actuator housing contact a mounting clevis that mounts the actuator housing to the vehicle. In actuator units having a slow response time (a long time to switch directions), this may not be a problem, or may be addressed with a limiting feature, such as a tang, located on the actuator housing next to one of the self aligning bearings. This limiting feature is formed close to a pivot point of the self-aligning bearings and often has a point or line of contact with the clevis. Although this limiting feature addresses the problem in a slow switching actuator, it does not allow for maximum torque capability and inherently has high impact loading when the actuator unit reverses direction at greater speeds. Accordingly, for high response systems (directional switching measured in number of times per second) a similar limiting feature located on the actuator housing does not solve the problem. Additionally, vibration or shock environments can also create high impact loading, due to the center of gravity of the actuator being offset form the line between the two self aligning bearings.
It should thus be appreciated from the above that it would be desirable to provide a compact and lightweight electro-mechanical actuator assembly that can withstand the relatively high magnitude shock and vibration levels present in high response systems. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.